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SEPTEMBER Vol.2 Issue 4 



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Altair 7000 Graphics Printer 



The tremendous flexibility of the 7000 Graphics /Printer, 
which acts as a printer, plotter and graphics device, makes 
it one of the fastest and most economical methods of electro- 
static printing. The new Universal I/O board for the Altair 
680b expands the I/O capabilities of the 680b beyond the 
one serial port on the main board. Thanks to the 88-Mux 
(24 Channel Multiplexer), the input capacity of the 88- 
Analog-to-Digital Converter for applications requiring a 
large number of analogs has been greatly increased. The 
new 88-S4K Memory Board now makes totally synchronous 
memory logic available to Altair 8800 users. 



The 7000 Graphics/Printer 

Although there are a number of methods used for 
printing computer output, electrostatic printing is 
finally being recognized as the only method which is 
fast, economical and, now with the MITS 7000, is also 
the most flexible means. In last month's G.N. we 
introduced the 7000 Graphics/Printer as a multifunc- 
tion, hard-copy output device which is plug compatible 
with the 680 and 8800 mainframes via one PI0 port. 
The enthusiastic response to the 7000 warrants a more 
detailed explanation of its operation and applications. 

The flexibility of the 7000 is due to eight print 
electrodes, driven directly by software, instead of 
the usual seven found in 5 x 7 matrix printers . Copies 
made from the printed output are actually more legible 
than copies of typed paper and can be made for about 
1$ per foot of electrosensitive paper. 

When the 7000 is used as a line printer, char- 
acters are generated using a 5 x 7 dot matrix. Altair 
BASIC supports three different sizes of character sets 
(each with upper and lower case) to produce line 
widths of 20, 40 or 80 characters in the four-inch 
wide printing area. The speed is 160 characters per 
second (80 characters per line) or 120 lines per min- 
ute. Different character sizes are selected with the 
CHR$ function in BASIC. 

The eighth or extra printing electrode in this 
unit provides symmetry along the horizontal and verti- 
cal axes to permit plotting. With the vertical dis- 
tance between electrodes equal to the distance between 
lines, there's no gap from line to line. This special 
feature makes the 7000 ideal for graphics. Pictures 
can be produced that show either a distinct outline or 
a sophisticated, detailed picture with shaded areas. 
When the eight-dot columns are printed close together, 

— Continued on Page Four - 



Keeping up with its innovative tradition, MITS 

has recently announced several new 

products which will greatly expand the capabilities 

of the Altair Computer 

system. 



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Letters to the Editor 

tot. La/uty B, CoWull o& Vqj> MoinoA, lorn., &2.wt In the. laltowlnQ 
comments on Hen/iy A/moid 1 4 Blofihythm Pfwgiam [ ComputeA HotoA, Juty, 
1976). 

The calculations of Yl and Y2 are incomplete. The program as 
listed on page ten of the July issue assumes that any year which is an 
integer multiple of four is a leap year. The correct leap year rule 
is: any year 'evenly' divisible by four is a leap year UNLESS it is 
•evenly' divisible by 100 (a 'century' year), BUT it is still a leap 
year if it is 'evenly' divisible by 400. To. correct the program, 
rewrite the lines shown here: 

5000 IF INT(Y1/4)*4<>Y1 THEN 5200 ;N0T A LEAP YEAR 

5100 IF INT(Y1/100)*1QQ=Y1 AND INT(Yl/400) *400<>Y1 THEN 5200 ;N0T A LEAP YR 

5150 Ll=l: GOTO 5300 

5200 LI =0 

5300 IF INT(Y2/4)*4<>Y2 THEN 5500 ;N0T A LEAP YEAR 

5400 IF INT(Y2/100)*100=Y2 AND INT(Y2/400)*400<>Y2 THEN 5500 ;N0T A LEAP YR 

5450 L2=l: GOTO 5600 

5500 L2=0 



10510 IF INT(Y2/4)*4oY2 THEN 10530 ;N0T A LEAP YEAR 

10520 IF INT(Y2/100)*100=Y2 AND INT(Y2/400)*400<>Y2 THEN 10530 ;N0T A LEAP YR 

10525 L2-1: GOTO 10600 

Note that lines 5200, 5500 and 10530 need not be re-written; lines 
5150, 5450 and 10525 are added lines. These changes will allow the 
program to work correctly for persons born before March 1, 1900. The 
leap-year rule stated above is correct for any year later than 1582, 
when the Gregorian calendar was adopted as a long-needed reform. 



Dear Ed. , 

In the last issue of Computer 
Notes , you mentioned a number of mag- 
azines interested in articles on 
microcomputers (and willing to pay 
for them). We are too, i.e., seek- 
ing good articles and willing to pay. 
In particular, we're interested in 
first person experience building com- 
puter kits and peripherals, and then 
getting them operational. But even 
more, we're trying to focus on "what 
do you do with it after it's built?" 
That is, applications. Things like 
a file system for LP records, menu/ 
shopping planning for various tasks 
and dietary requirements, kinetic 
video art, and, of course, games. 
But challenging games, cybernetic 
games, learning games. 

Contributions should be sent to 
Ms. Burchenal Green, Editor, Creative 
Computing, P.O. Box 789-M, Morristown, 
N.J., 07960. 

Sincerely, 
David H. Ahl, 
Publisher 

- Continued on Page Fifteen - 



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By Gale Schonfeld 



This month the Repair Department has 
asked me to relay the following message 
to you: 

WARRANTY ON MITS PRODUCTS 

The warranty on kits is 90 
days for parts. Labor is charged 
at $22.00 per hour for all com- 
puter mainframes and related 
products. The warranty on assembled 
items is 90 days for parts and 
labor. 

For detailed information on 
product warranty, please check your 
manuals. Remember - the warranty 
does not cover postage and handling 
to and from the MITS factory. 

HOW TO SHIP UNITS IN FOR REPAIR 

Packing - Make sure when pack- 
ing items to be returned for repair 
that all accessories are secured in 



place and that they are not "float- 
ing" inside or outside of the main- 
frame. Transformers should be 
bolted down or shipped separately, 
peripheral boards should be secured 
in their card guides and edge con- 
nectors, or packed in a separate 
box, disk drives must have the 
"block" secured in place, etc. 
Damage resulting from poor packing 
or packaging will automatically 
void your warranty . The Repair 
Department will advise you of any 
packing damage before repair action 
is begun. 



Packaging - If at all possible, 
items should be shipped in the orig- 
inal MITS box, padded well with 
newspaper or styrofoam beads. 
Styrofoam corner pads should be 
used to protect mainframes and ter- 
minals. Double boxing is preferred. 

Damages caused by the shipping 
agent - If an item received appears 
to have been damaged in shipment, 
the Repair Department will immed- 
iately contact the customer so that 
appropriate action may be taken for 
claims purposes. 

Mailing labels - Please be 
sure that your mailing label reads 
"ATTN:. Repair Department". We do 
have several departments which re- 
ceive in-coming packages and unnec- 
essary delays can be caused by mis- 
routing. 

Enclose a letter - Please be 
sure to enclose a letter explaining 
the problems you are having with your 



equipment. Examples of these pro- 
blems would also be helpful. Also, 
please remember to state who the 
actual owner of the computer or per- 
ipherals is (the owner, by our 
records , is the person or company 
listed in the "sold to" address on 
your invoice) . We ask this in order 
to prevent unnecessary charges due 
to lack of information on warranties. 

CHARGES 

Labor Charges - Labor charges 
are rated at $22.00 per hour for all 
mainframes and related products. 

-Continued on Page Fifteen - 



CO/V\pUTER 



Editor 



Production 



Andrea Lewis 

Tom Antreasian 
Al McCahon 
Grace Brown 




Page Two 



CN/September 1976 



TreKMng with the Altalr 



By Steve Lowe of Microsystems, 
Springfield, VA 



At the recent "STARTREK EXPO" 
held at the Hyatt Regency Hotel in 
Washington, D.C., MICROSYSTEMS was 
on hand with an impressive display 
of ALTAIR computers to introduce 
"Trekies" to the world of micro- 
computers. Several ALTAIR computer 
systems were displayed featuring a 
disk system, a talking ALTAIR, a 
T.V. Dazzler system using an Advent 
4' x 6' Videobeam T.V., and a game 
system using a second Videobeam T.V. 
as a terminal. 

Throughout the three day event, 
each of the systems proved their 
worth in attracting and holding 
convention-goers' attention while 
the MICROSYSTEMS staff answered 
questions and provided information 
to interested people. Many had no 
idea that microcomputers were so 
versatile and later dropped in at 
the MICROSYSTEMS showroom for more 
in-depth demonstrations of MITS 
computers and ALTAIR BASIC. 



One highlight of the show for 
the MICROSYSTEMS crew was a visit 
to their display by several of the 
original stars of the STARTREK T.V. 
series. George Takei, who plays 
Mr. Sulu in the series, was lured 
into the display room and tried out 
different versions of STARTREK 
games in front of a large crowd. 
During one game where the Enter- 
prise engages in combat with a 
similarly armed Klingon Vessel, 
George asked, "Do we have to fight? 
Why can't we negotiate?" Moments 
later a moan of anguish engulfed 
the room as the crowd watched the 
Klingon ship out-maneuver and des- 
troy the USS Enterprise. George 
redeemed himself, however, by win- 
ning his second battle. A newcomer 
to the world of microcomputers, he 
admitted that he could understand 
the fascination that made the 
MICROSYSTEMS display such a popular 
attraction at the show. Even before 
Gene Roddenberry (the producer of 
Star Trek) spoke later that day 
about the impact of computers on 
the future of humanity, MICROSYSTEMS 
had been proving that thanks to 
MITS, the impact of computers is 
already being felt around the world. 







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Moments before the Klingon' s des- 
troyed the Enterprise, George Takei 
(Mr. Sulu from the Star Trek T.V. 
series) pauses to ask the MICRO- 
SYSTEMS crew about "the possibility 
of negotiating with the Klingon 
vessel." 



Book Review 

By Linda Blocki 

The 
Gompleat 
Computer 




RIDDLE : What does a medical 
center, the Senate Watergate Com- 
mittee's investigative team and a 
Tibetan monastery have in common? 
ANSWER: a computer. Surprised? 
Thanks to new electronic develop- 
ments, the use of computers is 
quickly expanding to practically 
all areas of everyday American life. 

Information about computers is 
no longer confined to complicated 
articles by mathematicians and data 
processors. Many noncomputer spec- 
ialists are now doing some inter- 
esting research and writing, which 
is gradually replacing the public's 
confusion about all that hardware 
and software with beneficial infor- 
mation that anyone can understand. 

The Compleat Computer (1976), 
a carefully compiled collection of 
over 100 informative and sometimes 
humorous articles by noncomputer 

CN/September 1976 



specialists, seems to be the best 
publication so far to help expose 
people to the many diverse opinions 
about the use of computers. Author 
Dennie Van Tassel, user liaison in 
the computer center at UCSC and col- 
lector of computer miscellany, has 
filled his paperback book with a 
wide variety of selections from fic- 
tion, poetry, newspapers, cartoons, 
and advertising as well as more 
detailed articles that concern the 
computer specialists. Such well- 
known noncomputer experts as Norman 
Cousins, Ray Bradbury and Isaac 
Assimov are just a few of the writers 
whose articles appear throughout the 
book. 

Some of the different areas 
the articles cover include the story 
of a fully computerized poison con- 
trol center in a children's hospital 
in Missouri, a fictional account of 
a Tibetan monastery that used a Mark 



V computer to compile a list of all 
the possible names of God and a 
computer which acted as a key "mem- 
ber" of the Senate Watergate inves- 
tigative team by spewing out minute 
facts about any witness in a frac- 
tion of a second. 

In order to include as much 
material as possible, Van Tassel 
has capsulized the longer articles 
and selected only the "tastiest 
tidbits" for publication. His ex- 
tensive references following each 
article are helpful to the inter- 
ested reader who wishes to pursue 
a topic in greater depth. After 
each well-organized section of the 
book, a long list of questions and 
exercises is included to further 
aid the reader in exploring other 
various opinions about the use of 
computers . 

The book is divided into nine 
sections starting with three intro- 
ductory chapters — "In the Beginning," 
"How Computers Do It" and "The 
Software"- -which discuss the basics 
of computer operation. Articles 
appearing in this first section in- 
clude "The Development of Automatic 
Computing," "Computer Games People 
Play" and "Technology, McDonald's 
Collide as Students Best Burger 
Bonanza," a humorous article des- 
cribing how Cal Tech students used 
an IBM computer to print out 1.2 
million entry blanks and win a 
McDonald's contest. 

Continued on Page Fourteen 



Page Three 



- Continued from Page One — 

the effect is a very dark image. 
When the columns are printed farther 
apart, the image appears lighter. 

The 7000 is controlled by using 
a single port on an 88-4PIO parallel 
interface board. One section of the 
port provides the eight bits of in- 
formation to be printed, and the 
other section provides control. 

The control signals to_ the 7000 
are: (1) MOTOR ON, which starts the 
motor running while the print head 
remains disengaged, (2) PRINT, which 
engages the print head to begin tra- 
veling across the page and (3) LINE 
FEED, which causes a line feed with 
no print head movement. 

The control signals from the 
7000 are: (1) CT or character timing 
pulse. The first pulse defines the 
left-hand margin once the print head 
has begun to move, (2) DT or dot 
timing pulse. There are eight dot 
pulses for each character pulse. 

Each time a new column of in- 
formation is to be printed, the 
appropriate data bits are forced low 
(logic "0") by the 4PI0. Each low 
data line causes the related print- 
head electrode to discharge to the 
paper. This produces one dot. In 
all there are more than 500 eight- 
dot columns in a line. 



To print characters, seven elec- 
trodes are used to provide a one-dot 
space between lines. In the plot 
mode all eight electrodes are used 
so that there's no space between the 
lines that make up a plot. 

The software required to use the 
Altaif 7000 Graphics/Printer as a 
line printer has been integrated into 
the BASIC interpreter. In order to 
list or print using the 7000, the 
LPRINT or LLIST commands are used. 
In order to change the character 
size, an LPRINT command must be 
issued which includes one of the 
following three special characters: 



CHR$(1) 
CHR$ (2) 
CHR$ (3) 

Example: 



prints 80 characters/ line 
prints 40 characters/ line 
prints 26 characters/ line 



LPRINT CHR$(1); "TEST SMALL CHARACTERS" 
LPRINT CHR$(2);"TEST MEDIUM CHARACTERS" 
LPRINT CHR$(3);"TEST LARGE CHARACTERS" 

produces the following output: 



Note : If a new character size is 
not requested, the most recently 
requested character size will be 
used. 

Except for one assembly lan- 
guage subroutine, the software for 
using the Altair 7000 Graphics/ 
Printer as a plotter is written 
entirely in BASIC language. This 
will allow the user to make his own 
custom modifications to the standard 
software. It will also allow him to 
save room in memory by removing sub T 
routines that are not required. 



The image to be printed is 
stored in memory in a buffer with 
each bit representing a dot in the 
picture. If the bit is turned on, 
the corresponding dot is present. 
If the bit is turned off, the cor- 
responding dot is absent. A 256 
byte segment of memory represents 
the 8 rows of 256 dots printed on 
one pass of the print head. In 
order to cause this 8 by 256 segment 
to be printed, a single call to the 
assembly language routine is re- 
quired. 

Since an 8 by 256 dot picture 
is far too small to be of any prac- 
tical use, the plot routine uses a 
number of these 8 by 256 elements to 
compose a picture. The standard 
number is 32, and this requires an 
8K buffer for the image. The user 
may increase or decrease this number 
by altering a single BASIC statement 
as his heeds require or his memory 
permits. 



There are BASIC subroutines 



for: 



1) performing initialization - set- 
ting buffer size, location, etc. 
printing the entire buffer 
clearing the buffer 

4) marking a dot 

5) writing a character 
writing a string for label 
calculating scaling factors 
plotting a point 
drawing a line 



2) 
3) 



6) 
7) 
8) 
9) 



Here is some sample output: r] 



7000 Graphics/Printer Specifications: 

Price and availability: $785, 60 

days 

Printing medium: Electrosensitive 
paper -?(5 inches 
..; '. '• vide) '■* 



Page Four 



Horizontal 
resolution: 


A. Internal timing- 




80 dots/inch 




B. External timing- 




better than 128 




dots/inch 


Vertical 




resolution: 


65 dots/inch 


Printhead 




speed: 


0.0175 inches/msec . + 




0.1% 



Timing markers: A. 



B. 



Every 1/80 inch 
of printhead 
travel (DT) 
Every 1/10 inch 
of printhead 
travel (CT) 



Plotting speed: Two lines per second, 
8 dots vertical 

Input raster: Eight-bit parallel 

Power: 115V AC. 36 VA 

Weight: 14 lbs. 

Interface: 1 PIO Port (88-4PI0 or 
parallel port on 680b 
Universal I/O Board) 

The 680b Universal I/O Card : 

The 680b Universal I/O card 
provides two parallel ports and one 
serial port to greatly enhance the 
I/O capabilities of the Altair 680b 
while occupying only one slot on 
the expander board. 

Parallel Ports 




The design of the Universal 
I/O's two parallel ports is based 
upon a Peripheral Interface Adapter 
(PIA). The PIA contains all control 
and data registers, thus most options 
are software selectable. These op- 
tions include data direction (each 
data line can act as an input or an 
output), and interrupt/control struc- 
ture. The Universal I/O can be ex- 
panded up to two parallel ports. 

Parallel Port Selection: 



Each Universal I/O card requires 
16 address lines. Hardware sets the 
upper 8 address lines (A15 to A8) 
to F0 (hexadecimal) for all 1/0 
ports. These addresses are F0XX. 

Address lines A 7 through A4 
and their complements A7 through A4 
are user-selectable. With these 
addresses there are 16 different 
address locations for the Universal 
I/O (4 addresses are reserved for 
future use) . 

Address lines A3 and A2 select 
between 3 ports. A3 addresses the 
parallel ports or the serial port. 
A2 selects a particular parallel 
port . 

Each PIA contains 2 sections. 
Sections A and B each contain two 
channels, control status channel 
and data-data direction channel. 
Address lines A0 and Al enable the 
selection of port section, A or B, 
and the selection of control status 
channel or data channel. If the two 
parallel ports are addressed at F008 
and F00C, the port, section and 
channel addresses would appear as 
follows: 

(Refer to Figure One) 

CN/September 1976 



Figure One 



ADDRESS 


IC 


SECTION 


CHANNEL 


F008 
F009 
FOOA 
FOOB 
FOOC 
FOOD 
FOOE 
FOOF 


B 


A 


CONTROL/STATUS 


DATA-DDR 


B 


CONTROL/STATUS 


DATA-DDR 


A 


A 


CONTROL/STATUS 


DATA-DDR 


B 


CONTROL/ STATUS 


DATA-DDR 



The following block diagram illustrates the internal 
structure of a PIA, 



MPU 



PORT 



I/O DEVICE (S) 



Data In 



Data Out 



Address 
Buss 



Read 
Write 



A 

Section 



-*■ 


CA1 


CA2 


Data In/Out 

«B ■» 



Interrupt 
1 



IRQ 



B 



Section 



1 

Interrupt 
I 



(8 lines) 



CB1 



CB2 



Data In/Out^ 
(8 lines) 



(Refer also to "Software Initializa- 
tion of Parallel and Serial I/O 
Boards" by Patrick Godding, Computer 
Notes, June, 1976, pp. 14-17.) 



All lines are switch-selec- 
table for RS-232, TTL levels or 
20 milliamp current loop (TTY) . 
The serial port is programmable 
for nine or ten bit transmission 
as follows: 

a. 7 data bits .+ parity bit (odd, 
even, or none) + 1 or 2 stop 
bits; 

b. 8 data bits + 1 or 2 stop bits; 

c. 8 data bits + 1 stop bit + 
parity bit (odd or even) 

The transmit and receive inter- 
rupts enable or disable under soft- 
ware control. The Universal I/O 
provides an onboard, crystal- 
controlled clock that allows user 
selection for any of 13 baud rates 
by positioning a dip switch. 

The Selectable Baud rates are: 



300 
150 
110 



Universal I/O Board Specifications : 

Level Selection: Switch selectable, 
TTL, RS232, TTY 

Baud rate 

generator (ACIA) : Crystal-controlled 

CMOS Divider 



50 


2400 


75 


9600 


134.5 


4800 


200 


1800 


600 


1200 



Device 
Connection: 



(fully expanded) 12 
conductor cable, 10- 
pin removable connec- 
tor on board and 25 
pin connector (ACIA) . 
Three removable flat 
cables with a 24-pin 
plug on the board and 
a 25-pin connector 
passed through the 
back panel (for PIAs 
and other parallel 
interface) . 



680b Mb slots: One 



The Universal I/O with only one 
PIA parallel port can handle two in- 
puts (such as a paper tape reader 
or keyboard) or two output devices 
(such as a paper tape punch and 
printer) or any combination of cus- 
tom applications. A Universal I/O 
with two PIA parallel ports has 32 
data lines (each group of eight is 
individually selectable). All data 
lines are fully TTL compatible. 
Eight of the 16 lines are capable 
of directly driving the base of a 
transistor switch (1.5v at lma) . 



Serial Port 



The design of the Universal 
l/0*s serial port is based upon an 
Asynchronous Communications Inter- 
face Adapter (ACIA). The ACIA allows 

CN/September 1976 



serial data to be taken in on its 
receive line and transfers the data 
onto the Data Bus, or data can be 
entered from the data bus into the 
ACIA and then sent out the transmit 
data line in serial form. 

The ACIA contains both control 
and status iregisters. Five control 
lines allow maximum utilization of 
sophisticated terminals. The five 
control lines are: (1) transmit 
data, (2) receive data, (3) data 
carrier detect, (4) clear to send 
and (5) request to send. 

The 8-bit Status Register 
allows for greater control and 
handshaking ability by indicating 
received data available, trans- 
mitter buffer empty, carrier de- 
tect, clear to send., . framing (error, 
received data overflow, parity 
error, and interrupt request. 



Power: +5 volt at approximately 
350 milliamps fully ex- 
panded. Typically 27 mil- 
liamps @ +16 volts. Typi- 
cally 10 milliamps @ -16 
volts. 



Bit Configuration: 



Software selec- 
table for seven 
or eight bits, 
one or two stop 
bits and odd or 
even parity PIA. 



88-S4K Memory Board : 

An ideal addition to the Altair 
8800 series computer is the 88-S4K 
Synchronous 4K Memory Board, which 
has many outstanding features in- 
cluding totally synchronous design 
logic. This means the memory re- 
lies solely on the CPU for timing 
signals - no single shots and no 
critical on-board timing. 
•Continued on Page Nine— Page Five 



Troubleshooting the 680b 



by Rich Haber 




We have been very impressed in the repair department by how few 
680b 1 s have been sent back to us. Kit builders have been doing a really 
good job assembling and troubleshooting their units. If you are having 
any trouble with your 680b, the troubleshooting aids on pages 17-19 in 
the Theory of Operation Manual will help you track down some of the most 
common problems. 

Apparently not everybody received or noticed the errata sheet 
explaining that Q2 and Q3 and Q100 were silkscreened incorrectly on some 
of the main boards. The emitters were marked where the collectors should 
be and vice versa. The correct positioning for these transistors is 
shown in Figure 1. There was also an error on page 30 of the Assembly 
Manual and page 10 of the Operator's Manual concerning the Baudot inter- 
face. The values for R401 and R400 were reversed and a diode (D402) was 
left out. See Figure 2 for the correct configuration. 

Here is a list of some common problems with the 680b and how to 
track down the causes. 



Figure 1 



R40I 
-220-A- 



R402 
22K 



JUMPER 




- AO , .._D402 
R403 IN9U 
180-A. 

BAUDOT 



Figure 2. 



altair 8800b 

Assembly Manual 
Corrections: 



(Di spl ay/Control Board) 

#1 - Capacitor C7 should be ommitted 
and resistor R75 should be re- 
placed by a jumper wire. This 
filter circuit is not necessary 
since it will attenuate the 02 
input to IC SI -3 too much. 

#2 - When installing the resistor 

pack (page 5-24) it is necessary 
to clip off the last three leads 
at the end furthest from the dot 
on the resistor pack. There are 
no holes on the PC board for these 
leads and these three resistors 
are unused. 



Page Six 



680b Troubleshooting 
1. All address lights except AO lit. 

This indicates that the computer is lo cked in the reset mode. This 
can be verified if pin 40 of the MPU (RES) is LOW. Probable causes: 



a. 
b. 
c. 



Q2 and Q3 are in backwards (silkscreen shows C § E reversed) 

Solder bridge on transistor lands. 

No phase 1 clock signal to IC K pin 10 on front panel. If 

true, then check pin 2 of IC pp. 

Bus line 54 shorted. 



2. MPU always running. 



This can be verified if pin 2 of MPU (HALT) is HIGH, 
causes: 



Probable 



a. No 02 phase 2 clock signal to IC K pin 2 to retrigger the one- 
shot; if so, then check PP-4. 

b . IC I or K defective (check logic) . 

c. Q4 or Q5 in backwards, shorted or defective. 

3. Can't deposit. 



a. 

b. 



c. 
d. 
e. 

f. 

g- 



Make sure RAMs are strapped to the address you want. 

Check to see if pin 34 of the MPU (R/W) goes LOW when the deposit 

switch is toggled. If 34 won't go LOW, look at 1-12 on front 

panel and trace back. 

BA (pin 7 of MPU) should be HIGH. 

IRQ (pin 4 of MPU) should be HIGH. 

IC M pin 12 should be HIGH for read, pulse LOW for deposit. 

Does 02 appear at pins 1 and 2? 

AA-8 should be LOW. If not, and all AA inputs are HIGH, look 

for a short on this line. 

Check for solder bridges on RAMs. 



4. Can't deposit at any one bit. 

First interchange RAMs and see if bad bit changes. If it does, then 
the RAM is bad. If not, make the following checks on the bad bit 
(leftmost RAM is bit 0): 

a. Pin 13 should be LOW. 

b. Pin 10 should be HIGH. 

c. Pin 3 should be HIGH to read and pulse LOW to write. 

d. Is data appearing at DI (Pin 11)? Is data appearing at DO 
(Pin 12)? If not, check logic at NAND gate and inverter on 
output (pin 12) . Outputs of NAND gates should be HIGH for a 



"1" and LOW for a "0" 



Failure here could involve laborious 



tracing for solder bridges or shorted IC. _ c on tinued - 



CN/September 1976 



Defective monitor. 

Check pin 14 of PROM (chip select). It should go LOW when reset is 
toggled. If not, check to see that: DD8 is LOW, GG13 is HIGH, HH4 
is LOW and NN40 is LOW while resetting. 

If the monitor fails to print a period, it is occasionally due to 
two or more addresses being shorted together. Toggle each address 
switch separately to see if the LED lights. If a LED fails to 
light, position all the address switches up. If the LED comes on, 
then there is a short between addresses. You can isolate which one 
by putting the switches down one by one. 

I/O problems. 

Pins 2 and 6 of the ACIA should be HIGH after initializing the moni- 
tor (with 680b in terminal option), otherwise a short is indicated. 
Pins 3 and 4 should have a square wave signal equal to 16 times the 
baud rate; look for a .568 msec, period for 110 baud, .208 msec, 
for 300 baud. NOTE: R15 should be IK ohm instead of 4.7K. Do not 
bother to replace it unless the voltage at the right side of R15 is 
below TTL levels. If the voltage is very low, IC Z is probably bad. 

The most common causes of problems on units we have received have 
been : 

a. Solder bridges and cold solder joints (especially on 100 pin 
connector) 

b. Incorrect parts placement 

c. Incorrect hardwire strapping 

d. IC pins bent under chip 

I would like to recall your attention to the problem mentioned in the 
June Computer Notes ("Altair 680b Hardware Notes," page 9). If the 
MPU is given an invalid instruction to execute, it cannot be reset 
through the front panel switch. Instead, power must be turned off 
and on and then RESET must be activated, thereby erasing memory. To 
correct this, do the simple modification that is outlined in the 
article. 
Here is a convenient check list of logic levels for troubleshooting: 

Status (MPU Stopped) 

LOW T 

01 

HIGH 

LOW 

HIGH 

HIGH 

HIGH (pulses LOW 
during deposit) 
02 

HIGH 
cy = 16 x baud rate 

LOW 

HIGH 

tied to A0 

HIGH 

02 

HIGH 

HIGH (pulses LOW 

during deposit) 

HIGH 

same as front 
panel switches 
same as front 
panel lights 
LOW when addressed 

LOW when addressed 
Continued on Page Ten 



Chip ID 


Pin 
2 


Label 


MPU NN 


HALT 




3 


01 (phase 1 clock) 




4 


IRQ (interrupt request) 




5 


VMA (valid memory) 




6 


NMI (non maskable 
interrupt) 




7 


BA (bus available) 




34 


R/W (read/write) 




37 


02 (phase 2 clock) 




40 


RES (reset) 


ACIA J J 


3&4 


clock square wave freque 




9 


CS2 (chip select 2) 




10 


SSI 




11 


RS (register select) 




13 


R/W (read/write) 




14 


enable 




7 


IRQ 


RAMs C-K 


3 


R/W-P (read/write-prime) 




10 


VCC 




11 


DI (data in) 




12 


DO (data out) 




13 


CS (chip select) 


PROM T-V 


14 


CS (chip select) 


CN/September 1976 





Altair Users 



Larry Landsuerk 
2320 N. 56th Lane 
Fort Smith, Arkansas 



72901 



Ronald W. Moore 

A Div. USS America CV66 

FPO, New York 09501 

Robert M. White 
5240 Kootenai St. 
Boise, Idaho 83705 

Carl Knipp 

Box #1 

Cary, IL 60013 

New Address for: 

Capt. James K. Bostick 

Tuslog DET II 

PSC Box 2324 

APO, New York 092.24 

Jim Henley 

420 Bankcroft Ct., #8 

Rockford, IL 61107 

Computer Clubs 



Houston Texas 

HAMCC 

David M. Fogg, President 
4223 S.W. Fwy. , #203 
Houston ,VTX 77027 
(713) 626-2935 

The HAMCC meets on the second Friday 
and the fourth Tuesday of each 
month. 

Rockford, Illinois 

Anyone interested in forming a club 
in the Rockford, Illinois, area 

should contact: 

Jim Henley 

420 Bancroft Ct., #8 

Rockford, IL 51107 

1-815-399-6558 




HARD 
WARE 



Page Seven 



Something Sweet 

for your 
altair 680-b 



MITS is pleased to announce the development of a 16K static card for the 

Altair 680b. With an access time of 215 nanoseconds and low power consumption of 

5 watts, we feel that this is an excellent addition to the Altair 680b. 

To sweeten the pot even more, we are including a free copy of Altair 680 BASIC, 

assembler, and text editor on paper tape. ($275 value) 

Altair 680 BASIC is identical to the 8K BASIC developed for the Altair 8800. 

Features include Boolean operators, the ability to read or write a byte from any I/O 

port or memory location, multiple statements per line, and the ability to interrupt 

program execution and then continue after the examination of variable values. 

Other features of Altair 680 BASIC include variable length strings (up to 255 

characters), with LEFT$, RIGHTS and MID$ functions, a concatenation operator 

and VAL and STR$ to convert between strings and numbers. Both string and 

numeric arrays of up to 30 dimensions can be used. Nesting of loops and subroutine 

calls is limited only by available memory. Intrinsic functions include: SIN, COS, 

TAN, LOG, EXR SQR, SGN, ABS, INT, FRE, RND and POS, in addition to TAB and 

SPC in PRINT statements. Altair 680 BASIC takes 7K bytes of memory. 

MITS has also developed an expander card for the Altair 680b that lets you add up 

to three boards inside the main case. Read "Computer Notes" for announcements 

of additional Altair 680b boards. 

PRICES: 

Altair 680-BSM, 16K Static Memory Board, including Altair 680 BASIC, assembler 

and text editor $685.00 kit 

$865.00 assembled 

Altair 680-MB Expander Card with one Edge Connector $24.00 kit 

Altair 680 BASIC (purchased separately) $200.00 

Altair 680 assembler and text editor (purchased separately) $ 75.00 

PRICE APPLIES ONLY TO PURCHASERS OF ALTAIR 68OD COMPUTER 

Prices, specifications subject to change. Allow 30-60 days for delivery. 
MITS, Inc. 2450 Alamo S.E. /Albuquerque, New Mexico 87106 




Page Eight 



CN/September 1976 



- Continued from Page Five - 

There are no wait states so that the 
CPU runs at maximum speed. 

The 88-S4K provides 4,096 
bytes of Random Access Memory while 
consuming very low power. Each 
board contains memory protect cir- 
cuitry and address selection cir- 
cuitry for any one of 16 starting 
locations in increments of 4K. 
The 7 entire 4,096 bytes of memory 
can be protected by switching to 
PROTECT. A DIP switch is used for 
board selection with no hardwire 
jumpers, and test points have been 
installed at important signal out- 
puts for ease of checkout and 
troubleshooting. Ferrite beads 
are used on all common supply lines 
for noise isolation. 

For ease of assembly, an 
epoxy solder mask on areas not to 
be soldered has been added, as well 
as sockets for all memory ICs, 
which provide easy installation and 
removal of the ICs. Included with 
the 88-S4K is a well -documented 
manual with detailed theory and 
troubleshooting sections and step- 
by-step assembly instructions. 

88-S4K SPECIFICATIONS 

RAM Access Time: 200-300 ns. 

Power Requirement 
(worst case) : 

+5V current - 450 ma (max.) 
+12V current - 290 ma (max.) 
+12V current (uns elected) - 
10 ina (max.) 

Memory Array: 4,096 8 -bit words 

Dimensions: 10" x 5" 

Altair Slots: One 

Price: $155.00 kit, $255.00 assem. 

Availability: Within 60 days of 
order . 



The 88-MUX (24-Channel Multiplexer) : 

The 88-MUX, companion card to 
the 88-Analog/Digital Converter (88- 
ADC — see page 8 of the August issue 
of C.N.) , will expand the input 
capacity of the 88-ADC for applica- 
tions requiring a large number of 
analog inputs. 

The 88-ADC is actually a 
stand-alone card for many systems, 
because it contains an on-board 
8-channel multiplexer. However, 
for a majority of system layouts, 
the real potential of the ADC and 
MUX conversion system lies in the 
ability of the MUX to process more 
than eight signals. By using four 
88-MUX cards, it is possible to 
process up to 96 analog signals! 

Another advantage of using the 
88-MUX is the optional differential 
input. With simple modifications, 
the card can be set up to handle a 
differential input on each channel. 

CN/September 1976 



As a bonus, the gain and scale 

factoring of each channel can be 
set independently, giving extreme 
flexibility in system design. In- 
put filtering can also be added to 
provide the desired roll-off 
characteristics . 

An appropriate interface cable 
is provided with each ADC and MUX 
pair. (For more than one 88-MUX 
per system, a cable is required for 
each MUX card.) 

Specifications for the 88-MUX (24- 
Channel Multiplexer) : 

Price: $319, assembled only. 

Availability: within 60 days of 
order. 

Gain: Up to 1000 

Input Impedance: 1000 megohms 

Offset: 5MV (max.) 

Input Signal 

Level: (-4 to +10v) 

(-10 to +4v) 

(-5 to +5v) 

Settling Time 

to .01%: 15 microseconds (max.) 

P.S. requirements: +5vS40MA 

+15v@180MA 
-15v@180MA 



(See Computer Notes, August, 1976, 
page 8, for specifications jan the 
88 A- to-D Converter.) 



r* ~i 


F<: ! 


— 


i = O 5 


u L 


S Lj !z= 




1 ra X R fA 


["--; - 








: _. 


: ■ ."' 






CJj 






; -_ ; . = : : J : : .- 1" "" -. I ; r : =. r _. 












■ ■ M 




= R- 1 N N N N N 5 h i 5< = & 4- « H 




M i 




— |-.j i -.' — 1 --■■ = \*\ £? "x ^ = ;_• -.+ : 4.; j-j j 




; " _ : P" 


— 


j_ y- -j W P 1 "-"' -=" W : j ! i ''■ = ^- ! : ~- = :■*-: '*-* 


i •— 


ip r" 


~\~ 


liRN 


■-: ; -- 


Pjr 






















4 9 


RE 




C- L. EI H K J f'l H b b.. h:^ U P F" 




F G 


~ 


1 J??. ."*„ _f. =": -\- ! LJ -1- PI -* f a '^" I'i 


~ : ":t : 


K t_ 




M B R K J.i'iRGE t; u r F t_ 



Q R 



a R : 



T : ~ V =z : 

FOR r 



Example of Program printed by 
Graphics Printer.(73% of full size.) 



Example of Graph printed by 
7000 Graphics Printer.(73% of 

full size.) 




, m ■ , , '• , : |||: : ; • •', . ;;|||| ■ .. : : : | ; |||' : ; '■ ;1 ?|||f^ , : |iPy 













Example of 3 -Dimensional House 
projected by 7000 Graphics Printer. 
(73% of full size.) 



Page Nine 



software 
corrections 



Users have discovered the following 
mistakes in two of our software 

programs: - 

#2-3-761 , page 18: 

Memory location 1 .042 166 should 
read 1 042 301 

Page 31: 

Memory location 2 015 014 should 
read 2 015 013 

#6-1-763, Line 570: 

A=FNR(N05)+INT (N0+5) : B=FNR(Nl/20)+ 
INT(Nl/20) : C=FNR9L2/50) 

should read A=FNR(N05)+INT (N0/5) etc. 

This change makes it possible to 
win the game. 




GDQLaB 




2450 Alamo SE 
Albuquerque, NM 87106 



505-243-7821 



TROUBLESHOOTING 

Continued from Page Seven — 

Here are three test programs that are useful in checking out your 
680b. 





Jump 






0000 


7E 


jump 




1 


00 






2 


00 






Add 


Two Bytes 




0000 


86 


LDA 




1 


your 


choice of 


data 


2 


C6 


LDA B 




3 


your 


choice of 


data 


4 


IB 


ABA 




5 


B7 


STAA 




6 


00 


LDC 




7 


40 






8 


7E 


JMP 




9 

A 


00 

when using 
00 


fron 




or 






9 

A 


FF 

when using 
AB 


term 



when running only A0 § 1 should be lit 





Echo Routine 


f 0000 


86 


V x 


03 


reset and \ 




\ 2 


B7 


initialize l 




1 3 


FO 


ACIA 




J 4 


00 




5 


86 




6 


Dl 




7 


B7 




8 


FO 


I* 


00 


( A 


B6 


check to 








B 


F0 ;wait for data 


see if a 






J C 


00 


character >y 






D 


47 ;rotate right 


has been 








E 


24 ; branch 


received 






V F 


FA 


f 0010 


B6 


input } 




< 1 


F0 


data 1 




\ .2 


01 


f* 


F6 


check to 








4 


FO 


see if 








5 


00 


ACIA ready J 




\ 6 


57 ; rotate 


to output 








7 


57 ; rotate 




8 


24 




V9 


F9 


/OOOIA 


B7 


B 


FO 


output I 




< c 


01 


data J 




D 


20 


V B 


EB 


jump 


to 0000 




and 


type character 



Should you need more help with 
your 680b, please feel free to call 
us. If you decide not to repair the 
unit yourself, please send it in. 
There is currently no backlog of 
680b 's in repair and return should 
be relatively prompt. 



Reset, run, stop and sum of data should appear at address 0040. 
Page Ten 



CN/September 1976 



HAM 

on the side 

By Wayne Cronin 

As the only licensed ham at 
MITS, I've been elected to edit a 
new ham-oriented column for Computer 
Notes . I'll be using this space to 
pass along ideas for adapting com- 
puters (hopefully ours!) to ham pur- 
poses. That means I'll need lots of 
input from readers, and I'm sure many 
of you have some good ham applica- 
tions ideas to share with us. 

ASCII, HAMS, AND THE FCC 

If you have your own computer 
system, you probably have some kind 
of I/O device that uses ASCII code. 
If you could use your terminal to 
key your rig, you could use your 
computer to get in on RTTY activity, 
or to communicate with another ham's 
computer via radio. Unfortunately, 
since current FCC regulations allow 
only Baudot code transmission, you 
have to use some kind of hardware or 
software code conversion scheme to 
accomplish either of these functions. 
This is a needless complication and 
a waste of processor power. 

The only way to get the rules 
changed is to petition the FCC. If 
you're thinking of submitting a pet- 
ition, here are a few things to 

think over first. 

Any new rules changes should be 
general enough to allow us to take 
advantage of future advances in the 
state of the art automatically; we 
don't want to have to cut more red 
tape each time something new comes 
along. If a proposal for a rules 
change is too specific in its word- 
ing, we could be neatly backing our- 
selves into a corner. 

As an example, let's suppose 
that the FCC adopted new regulations 
based on a petition by amateurs re- 
questing the use of ASCII. This 
could be interpreted as prohibiting 
Baudot. If this happened, we would 
instantly lose compatibility with 
Baudot equipped DX stations, and 
hundreds of U.S. hams using older 
equipment would be forced to use the 
same type of hardware or software 
conversions we had hoped to avoid. 

I really don't think that any- 
body would submit such a restrictive 
proposal (much less that the FCC 
would adopt it) . This is just an 
extreme example of the dangers of 
hastily written, narrowly worded 
proposals . 

If any of you are considering 
submitting a rules change request 
concerning the use of ASCII, I'd 
like to hear your suggestions for a 
generalized wording that would allow 
us to use ASCII and Baudot now and 
also leave a few "loopholes" for 
future developments. (Don't forget 
to consider the possible effects of 
the proposed new bandwidth regula- 
tions on HF computer communications.) 

CN/September 1976 



September Software Contest 



By Stan Webb 



The first place winner this 
month is Kenneth Aird with his 
FORTRAN Cross Assembler for the 680. 
This program is beautifully written 
and well documented. With the ad- 
dition of this program, we now have 
three FORTRAN Cross Assemblers in 
our library. Consequently, we 
cannot accept any more programs of 
this type. 

Second place goes to Keith 
Fischer for his BECO Text Editor. 
This program, written in Altair 
BASIC, is considerably more power- 
ful than the BASIC Editor, and 
would be a valuable addition to a 
BASIC system. The user documenta- 
tion is fairly good, but it lacks 
much program documentation. 

Erik Mueller takes third place 
with his MINOL Interpreter. MINOL 
is a subset of BASIC designed to 
run in less than 4K of memory. This 
subset is very restrictive when com- 
pared to a large BASIC, but is un- 
doubtedly easier to work with than 
machine language. This program was 
previously published in the April, 
1976, issue of Dr. Dobb's Journal 
of Computer Calisthenics and Ortho- 
dontia . 

Due to the lack of competition 
in the subroutine category, no prize 
will be awarded this month. 



HAM SOFTWARE (and the lack of it) 

If any of you have written ham 
applications software for 8080 or 
6800 based machines, please consider 
submitting it to our software library. 
If I receive any programs that aren't 
excessively long, I'll try to get a 
listing into Computer Notes . Some of 
you may be able to contribute infor- 
mation that could be used as the 
basis for a ham software package. 
An example would be a set of mathe- 
matical formulas for predicting sate- 
llite orbits. Information like this 
made available through Computer Notes 
could result in a lot more programs 
for the library. 

COMPUTER NETS? 



If you know of any nets devoted 
to computer topics, please let me 
know, and I will spread the word. 
If you'd like to start a net, send 
me your suggestions for a band and 
time. 

NEXT 

Next month I'll talk a little 
about some of my own ideas for ham 
computers and software. I hope to 
have lots of your ideas to talk about 
also. Please write or call me at the 
MITS Repair Department with your 
comments and suggestions. 73. 



AUTHOR'S COMMENT: 

The library has a lot of mat- 
erial now, so I'd like to see our 
users put more effort into writing 
clean programs with good documenta- 
tion. The programs that are neatly 
typed on our submission forms and 
that are well documented are more 
worthwhile to other users than 
those that are hastily done and have 
no documentation. 



FIRST PLACE MAJOR PROGRAM 



#9-1-761 

Author: Kenneth Aird 
Length: 41,000 bytes FORTRAN 
Title: M6800 Cross Assembler 
Very well written FORTRAN Cross 
Assembler for M6800. 

SECOND PLACE MAJOR PROGRAM 

# 8-23-761 

Author: Keith Fischer 

Length: 150 lines Altair BASIC 

Title: BECO 

Powerful Text Editor. 

THIRD PLACE MAJOR PROGRAM 

#8-13-761 



Author: Erik Mueller 

Length: 7,000 (octal) bytes 

Title: MINOL 

Interpreter for a 4K subset of 

BASIC. 

#8-9-761 

Author: Alan Miller 

Length: 200 lines Altair BASIC 

Title: QUBIC 

Plays 3D tic-tac-toe. 

#8-10-761 

Author: Alan Miller 

Length: 7 lines Altair BASIC 

Title: Numerical Integration 

Numerical integration by Simpson's 

method and Trapezoidal Rule. 

#8-16-761 

Author: Roger Frank 

Length: 7 lines Altair BASIC 

Title: Memory Size 

This program resets BASIC memory 

sizes without restarting (for 3-2 

only) . 

#8-19-761 

Author: Alan Miller 

Length: 5 lines Altair BASIC 

Title: ARCS IN 

Program to compute arcsin and arccos, 

#8-26-761 

Author: Roger Frank 

Length: 22 lines Altair BASIC 

Title: Memory Test 

Program to test unused memory. 

#8-27-761 

Author: John Stanton 

Length: 52 bytes 

Title: 4PI0 KBD/PTR Loader 

Loads data into memory from keyboard 

and echoes it. 

#8-28-761 



Author: J. David Green 
Length: 168 lines Altair BASIC 
Title: Horse Racing 
A horse racing game that involves 
betting on the races . 

Page Eleven 



Technical Information 



• TM 



altair 

Floppy Disk (8 8-DCDD) 



The 88-DCDD consists of the 
Disk Controller and one Disk 
Drive with an interconnect cable. 
The Disk Controller consists of 2 
PC boards (over 60 ICs) that fit 
in the Altair chassis. The Disk 
Drive unit consists of a PERTEC 
FD-400, a power supply PC 
board, and a Buffer/ Address/ 
Line Driver PC board. The Disk 
Controller converts the serial 
data to and from 8-bit parallel 
words (one word every 32 
microseconds). The Disk 
Controller also controls all 
mechanical functions of the disk 
as well as presenting disk status 
to the computer. 

Software and System 
Features 

Altair Disk Extended BASIC is an 

enhanced version of Altair Extended 

BASIC with added capabilities for saving 

and loading programs, and for 

manipulating data files on disk. 

Altair Disk Extended Basic uses random 

and sequential files for storing 

information on disk. 

Utility software is included with Altair 

Disk Extended BASIC for copying 

diskettes, initializing blank diskettes, 

listing directories, etc. 

Disk bootstrap loader is available on 

paper tape, cassette tape, or PROM 

(used with 88-PMC PROM Memory 

Card). 

Hard sectored format (non IBM 

compatible) allows storage of over 

300,000 data bytes. 

Altair Disk Extended BASIC requires a 

minimum of 20K of RAM memory to 

Operate in. 

PROM Disk Bootstrap loader allows 

loading of Altair Disk Extended BASIC in 

less than 10 seconds from the time 

power is turned on. 




Hardware 

A. Description and Features 

The Disk Controller, which acts as the 
interface between the Altair and the 
Disk Drives, consists of 2 PC boards 
that fit in the Altair chassis. They 
require 2 slots in the Altair, contain 
over 60 ICs, and connect to the Disk 
Drives via an 18 pair flat cable. The 
Controller can address up to 16 drives. 
The Disk Drive Unit consists of a 
Pertec FD-400 drive in an Optima case 
5V high, 17" wide, and 17J4" deep 
(same width and depth as the Altair 
8800). Also in the Disk unit is a power 
supply and a Buffer/ Address card for 
selecting the drive and interconnecting 
multiple disk systems. A fan is included 
to maintain low ambient temperature 
for continuous operation. The Disk 
Drive units interconnect to each other 
in daisy chain fashion and to the 
controller using 18 pair flat cables and 
DC-37 type 37-pin rectangular 
connectors. 



Page Twelve 



CN/September 1976 



B. Hardware Specifications 

Access Time: 

Track to track : 10 ms. 

Head load and settle time : 45 ms. 

Average time to read or write: 

400 ms. 

Worst case - - 1135 ms. 
Rotational speed: 360 RPM (166.7 

ms/rev) 

Tracks: 77 per disk 

Sectoring: Hard sectored, 32 sectors 

per track, 5.2 ms/sector (non IBM 

compatible) 

Data Transfer Rate : 250,000 bits/sec. 
(one 8-bit byte every 32 microseconds) 
Maximum number of drives per system ; 16 

Data storage capacity : 310,000 

bytes per disk 

Data bytes per sector: 128 

Data bytes per track: 4,096 

Disk Drive head life: over 10,000 

hours of diskette to head contact 

Disk Drive MTBF : exceeds 4,000 

hours 

Disk Drive data reliability : not more 

than 1 in 10 9 soft (recoverable errors# ^ 

1 in 10 12 hard (non-recoverable errors 

Power: 

Controller: 1.1 amps at + 8V unregu- 
lated (from Altair bus) 
Disk Drive Unit: 11 watts 50/60 
Hz 117/220 VAC 

Diskette: Hard sectored, 32 sectors + 

index hole (Dysan #101, ITC #FD 

32-100) 

Disk Drive Unit Weight: 40 pounds 

C. Operating Principle . 

The Disk Controller cards provide the 
interface between the Disk Drive Unit and 
the Altair bus. Serial read data from the 
disk is converted into 8-bit parallel form by 
the controller for transfer to memory via 
the CPU. Data is written on the disk by 
converting the 8-bit bytes outputted from 
the Altair CPU to serial form. All read and 
write data is transferred one byte at a 
time through the CPU. 

Disk Controller Board #1 controls I/O 
address selection, sector counting, read 
data, and disk status. Disk Controller Board 
#2 controls disk drive addressing, write 
data, and disk drive functions. 




Ordering information: 

1. 88-DCDD 

Includes: 
Set of controller cards 
1 Disk Drive Unit 
1 interconnect cable— 6 ft. long 
1 Assembly and Operators Manual 
1 Disk Extended BASIC Manual 
1 Blank Diskette 

2. 88-DISC 

Includes: 

1 Disk Drive Unit (117 VAC unless 
otherwise requested) 
1 Interconnect cable — 6 ft. long 
1 Blank Diskette 

3. Altair Disk Extended BASIC 
Requires a minimum 20K of memory for 

operation. 

Includes: 

Altair Disk Extended BASIC on diskette 
Altair Disk Extended BASIC Manual 
Paper tape or cassette magnetic tape 
bootstrap loader (specify when 
ordering) 

4. Disk Bootstrap Loader on PROM: 
Order 88-PMC (PROM Memory Card) 
and DBL PROM (PROM programmed 
with disk bootstrap loader routine) 

5. Manuals only: 

Disk Hardware Manual 

Altair Disk Extended BASIC Manual 



P£ DDDDS 



2450 Alamo S.E./ Albuquerque. New Mexico 87106 



CN/September 1976 



Page Thirteen 



altair 
ambassadors: 



MITS, Money, and You 



By Mike Hunter 



MITS, the originator and leader 
of the personal computing revolution, 
has developed a program to further 
extend support to those Altair users 
living in regions where Altair retail 
centers presently do not exist. The 
Altair Ambassador program will offer 
qualified individuals the opportunity 
to be local MITS Altair representa- 
tives in cities where computing 
interest is large, yet the likeli- 
hood of having an Altair dealership 
is small due to the relative size 
of the community. Thus, the Altair 
Ambassador will be able to give MITS 
support through the selling and ser- 
vicing of Altair computing equip- 
ment, for which he will receive a 
commission on each sale, and be 
able to do so using his home as his 
place of business I Personal com- 
puting will become even more per- 
sonal, for the local MITS repre- 
sentative will be a member of your 
community- -perhaps even yourself! 

If you live in a community 
where an Altair retail center is not 
available and you are an Altair 
System owner, you have met the 
first requirement on the way to 
becoming an Altair Ambassador. 
Another criterion is that the 
Ambassador have a working knowledge 
of MITS hardware and software so 
that he may offer technical assis- 
tance and repair capabilities to 
other Altair users. 



MITS will conduct weekend train- 
ing sessions for potential ambassa- 
dors which will include discussions 
of software capabilities, repair 
techniques, product scope, and sales 
techniques. Each applicant will be 
required to attend one weekend train- 
ing session at his expense. Upon 
notification of his acceptance into 
the program, the Ambassador will 
receive a program package including 
business cards, forms, catalogues 
and all current product literature. 

Thus, the Altair Ambassador 
will receive full support from MITS 
so that he may best sell to and 
service his community, while making 
money at the same time. The only 
investment the Ambassador need make 
is travel and lodging expenses for 
the weekend training session in 
Albuquerque. Thus, if you own a 
MITS Altair System, and reside in 
a city without an Altair retail 
center, you may very well be the 
local computer expert whose future 
is to be an Altair Ambassador. 



Please write for more infor- 
mation and an application form to: 

Altair Ambassador Program 
MITS, Inc. 
2450 Alamo SE 
Albuquerque, NM 87106 



Program 
Progress 



Due to the increased 
interest in developing 
programs for very specific 
needs, beginning next 
month we'll be offering 
"Program Progress" 
whenever possible. Designed 
to give readers an 
opportunity to suggest what 
programs they'd like to see 
in the Altair Software Library, the 
list of ideas will be published as 
long as you keep providing 
suggestions. We hope these 
suggestions for programs will be 
of particular interest to Altair 
owners . 




So send your ideas to 
COMPUTER NOTES, and we'll pass 
them on to our readers. 



Page Fourteen 



BOOK REVIEW 

Continued from Page Three 



The second portion of the book 
brings the reader up-to-date with 
chapters on "The Present and Po- 
tential," "Applications" and "Gov- 
ernmental Uses" of computers. In 
"Justice, the Constitution and Pri- 
vacy" Sam Ervin, Jr., U-S Senator 
from North Carolina, raises some 
interesting questions concerning 
the computer's role in government 
surveillance and the individual's 
right to privacy. On a more humor- 
ous side, Art Buchwald's "The Curse" 
warns of the horrible consequences 
a computer metes out when a defiant 
citizen dares to fold, bend and 
mutilate his phone bill and send it 
(with payment) back to the company. 



The book ' s final three chapters 
--"The Impact of Computers," "Con- 
trols or Maybe Lack of Controls" 
and "Your Future" — explore the many 
significant effects the computer 
has upon our everyday lives and the 
potential role it plays in our 
country's future. Among the var- 
ious articles in this section dis- 
cussing both sides to the computer 
questionnaire, "Computerized Dating 
or Matchmaking," "Computer Crime" 
and "Machines Hold Powers for Good 
and Evil." 



Interspersed among the many 
informative articles are imagina- 
tive poems, computer-generated 
illustrations and cartoons. 
Throughout the book, the famous 
comic strip character Doonesbury 
and his friend, Mark, marvel at the 
many wonders of the computer. A 
newspaper ad for computer operators 
convinces them that they have found 
their true vocation in life. "Earn 
$7,000, impress your friends. MEET 
GIRLS'" 

In addition to all that humor, 
intrigue and important information 
to both the computer and noncomputer 
specialist, The Compleat Computer 
offers fictional romance about a 
computer named Max who almost breaks 
up a marriage. For $5.95 a copy, 
who could ask for more? 



Copies of The Compleat Computer 
can be obtained directly from the 
publishers: Science of Research 
Associates, 1540 Pagemill Road, 
Palo Alto, California. 

Van Tassel has also published 
Program Style , Design, Efficiency 
Debugging and Testing (Prentice 
Hall, Inc.). 



CN/September 1976 



LETTERS TO THE EDITOR 

Continued from Page Two 

Dear Ed. , 

I am writing this letter for two 
reasons. Before I commence with the 
diatribe, however, I would like to 
say that I enjoy very much the 17K 
Altair 8800 system that is up and 
running at our house. We use the 8K 
version of BASIC. 

On the very first page of the 
BASIC Reference Manual you state 
that BASIC was originally developed 
at Dartmouth University. This is 
incorrect. I am a student at Dart- 
mouth College ; to myself and all 
other Dartmouth students and alumni 
this reference to the "university" 
is a slur. 

The distinction, seemingly 
minor, is historically and legally 
quite important. In 1818 the state 
of New Hampshire tried to take con- 
trol of the College and turn it into 
a state school. They were partially 
successful, in that Dartmouth Uni- 
versity was created. The University 
used the same classrooms, dormitories, 
and chapel as the College. Needless 
to say, there was considerable unrest 
from both students and faculty. 

In 1819 the problem reached 
the Supreme Court. Daniel Webster 
(class of 1801) argued eloquently 
for the College and triumphed. The 
Dartmouth College case was a land- 
mark decision that guaranteed the 
inviolability of legal contracts. 

So you see when you attribute 
BASIC to Dartmouth University, you 
credit an unenduring and illegal 
"splinter school" of the early 
1800' s. Please try to correct this 
error in subsequent printings of the 
BASIC manual. 

When working on the Dartmouth 
computer, I have found that the VAL 
and STR$ functions are useful. VAL 
takes a single string argument and 
converts it to a constant: 

X$="-17.69" 
X=VAL(X$) 



X equals 
opposite: 



■17.69. STR$ does the 



X=25*25 
X$=STR$ (X) 

Therefore, X$="625". Also useful is 
the POS function, which searches a 
string for the presence of another 
string and returns the substring's 
location: 

Q=P0S(A$,B$,C) 



POS looks for the location of B$ in 
A$ starting at location C in A$: 

A$="ALTAIR" 

POS(A$,"T",l)=3 

P0S(A$,"LTA",1)=2 

POS(A$,"Z",1)=0 

POS(A$,"LTA",3)=0 

Thank you for your time. 

Sincerely, 
John Sot os 

Ed. Note: STR$ and VAL are present 
in 8K and Extended BASIC, and the 
equivalent of the POS function in 
Extended BASIC Ver. 3.4 is INSCR. 



CUSTOMER SERVICE NEWS 

- continued from page 2 

Shipping and handling charges - 
Rates for continental United States 
shipments - Prepaid or UPS COD: 

$8.00 each for mainframes and ter- 
minals 

$3.00 for up to three (3) peripheral 
boards, add $1.00 per board there- 
after. 

We are unable to ship COD to 
the following: 



CD 

(2) 



(4) 



Post Office Boxes 
Companies or Educational Institu- 
tions 
(3) APO or FPO Addresses 

Foreign Countries (including 
Canada) 




Foreign Countries (including 
Canada) - Repair shipments will be 
made via Emery Air Freight Collect. 
Also, charges incurred for units 
coming in from foreign countries to 
MITS, e.g. customs charges, will be 
billed as part of the customer's 
repair charge. (These charges aver- 
age between $30.00 and $40.00.) 

Please remember to send in pay- 
ment for these charges, otherwise a 
delay will occur while we contact 
you for payment or COD authorization. 
We will accept for payment: Master 
Charge, BankAmericard, money order, 
personal check (three week delay for 
processing) or authorization for COD 
for charges under $15.00. Companies 
and educational institutions should 
remember to send in their Purchase 
Orders authorizing repair and return 
shipment charges. 

I hope this will help those of 
you asking what our procedure is foi 
returning items for repair. If you 
have further questions, please con- 
tact the Repair Department. 

See you next month - Gale 



Computer Notes Review, Volume I, is a collection 
of reprinted articles from previous issues of 
Computer Notes (April, 1975 through July, 1976). 
We have eliminated all editorial, fictional and 
advertising materials and have printed only the 
most informative and technical articles pertain- 
ing to Altair hardware (specs, modifications, 
troubleshooting) and software. This 94-page book 
is arranged in an 8 1 /2 x 11 format and is ready to 
insert in a 3-ring binder. The price of Volume I 
is $12.00. (Altair customers who have already 
ordered the Update Service will automatically 
receive Computer Notes Review, Volume I.) 



Please send me Computer Notes Review, Volume I. 

Enclosed is $ ' 

□ Check 

□ BankAmericard #_ 

D Master Charge # ' , : . 



NAME_ 



ADDRESS^ 
CITY 



STATE & ZIP_ 



M ITS/2450 Alamo S.E., Albuquerque, N.Mex. 87106 
505/243-7821 



CN/September 1976 



Page Fifteen 



One Slot! 




Altair"" 16K Static 



Almost too good to be true, the Altair 16K Static 
RAM board is easily the most advanced memory 
module yet developed for the Altair 8800, 8800a and 
8800b computers. 

Four Altair 16K Static boards add up to the entire 
64K of memory directly accessible by the Altair. 

The Altair 16K Static board offers two surprise 
features— minimal power requirements and fast access 
time. One Altair 16K Static board draws less current 
than any 8800 compatible 4K boards, thus four Altair 
16K Static boards can be plugged into the Altair 
8800 without beefing up the power supply. 

The maximum access time of the Altair 16K Static 
board is 215 nanoseconds, which makes this board 
the fastest Altair compatible static board in existence. 

The Altair 16K Static is now in full production. 
Special introductory price is $765 in kit form and 
$945 assembled. 



MAIL THIS COUPON TODAY 



Enclosed is check for $. 
BankAmericard # . 



| or Master Charge # 

. □ Altair 16K Static □ Kit □ Assembled 

' (include $3 for postage and handling) 

I □ Please send free information package and price sheet. 

I NAME 



ADDRESS. 
CITY. 



STATE AND ZIP. 



I MTTS/2450 Alamo SE/Albuquerque, NM 87106/505-243-7821 



L_ 



Prices, delivery and specifications subject to change. Allow up to bO days tor 
delivery. 

2450 Alamo SE/AIbuquerque, NM 87106/505-243-7821 



Page Sixteen 



CN/September 1976